"Teenagers need to be warned that the vapor produced by e-cigarettes is not harmless water vapor, but actually contains some of the same toxic chemicals found in smoke from traditional cigarettes," lead author Mark Rubinstein said. He's a professor of pediatrics at the University of California San Francisco.

This is the first known study to report on the presence of potentially cancer-causing compounds in the bodies of teens who use e-cigarettes.

The compounds found include acrylonitrile, acrolein, propylene oxide, acrylamide and crotonaldehyde. All are listed in the National Institute for Occupational Safety and Health’s Pocket Guide to Chemical Hazards.

In the study, Rubinstein and his colleagues at UCSF tested the urine of teenagers who vape. They then compared it to teens who both vape and smoke tobacco cigarettes and to those who don’t use either.

Levels of toxic organic compounds were up to three times higher on average in the e-cigarette users when compared to nonsmokers. In teenagers who used both, levels were up to three times higher than in e-cigarette users only.

Bottom line, Rubinstein said there’s no reason teenagers should be vaping.

"E-cigarettes are marketed to adults who are trying to reduce or quit smoking as a safer alternative to cigarettes,” he said. “While they may be beneficial to adults as a form of harm reduction, kids should not be using them at all."

(Sanofi via AP). This undated product image provided by Sanofi shows Praluent 75 mg, a drug sold by Sanofi and Regeneron Pharmaceuticals. It’s one of a new class of cholesterol medicines that lower cholesterol far more than statin medicines can. A key ...

A newer type of cholesterol drug modestly lowered heart risks and deaths in a big study.

A newer type of cholesterol drug modestly lowered heart risks and deaths in a big study.